Fluid-pressure brake.



PATENTED DEC. l2, 1905.

W. P. A. MAGFAR-LANE.

FLUID PRESSURE BRAKE.

APPLIoATIoN FILED JULY 1s. 1905.

og n. E. N W/ mi L` l s \N R 05 u s. N 3

r.- l g m $9* I w N d, f M 1 M N @1 i w ii 2 SHEETS-SHEET 1.

W fw d am m 1 N m, l WW m E H f lhmll m f v m M .N 1 M A m f w/ Hmmm Q mR n 1 R: Q R B H fx M mw. m mmm x Q PIo 7/ .UM Nm //l||\ w A w um l uw,w f ffff ,L am m4 RW y T W kw nv m, a W/A M m UNITED "srnwnnr OFFICE.

WILLIAM P. A. MACFARLANE, OF CHICAGO, ILLINOIS, ASSIGNOR TO RICHARDFITZGERALD, OF CHICAGO, ILLINOIS.

FLUID-PRESSURE BRAKE..

Specification of Letters Patent.

Iatented Dec. 12, 1905.

Application lecl July 18, 1905. Serial No` 270,216.

To @ZZ whom/ if may concern.-

Beit known that I, WILLIAM P. A. MAG- FARLANE, a citizen of the UnitedStates, residingat Chicago, in the county of Cook and State of Illinois,have invented certain new and useful Improvements in Fluid-PressureBrakes, of

i y service mechanism thereof, for the purpose of braking the caraccording to its empty and loaded weight, with the result that the carmay be braked with an increased pressure-when loaded. lIn the presentinstance, and as hereinafter described, my invention is arranged t forma part of the so-called "triple-valve device and to be arranged insubstantially the same caslng as the latter.

In the drawings, Figure 1 is a central sectional elevation of atriple-valve device embodying my invention; Fig. 2, asectional plantaken on the line 2 of Fig. 1 with a portion thereof broken away toexpose parts beneath,

and Fig. 3 a detail illustrating the running of some of the ports andpassages.

' In the present instance I have shown my invention applied to my formof triple valve I in which the brake-release mechanism, the

service mechanism, and the emergency mechanism are separate andindependent both physically and operatively; but it will be understoodthat I do not limit my invention to any specific form or character ofapparatus,

A plicable.

but contemplate using the same wherever ap- Inasmuch as the threemechanisms Just referred to do not constitute per se any part of mypresent invention, the same will' be described in a more or less generalmanner, but sufcient for a proper understandingof the construction andmode of operation of the new parts constituting my improvements orinvention.

The triple-valve device herein shown comprises a main valve body orcasing 1, having secured thereto in suitable manner the top cap 2,bottom cap 3, and supplemental casing 4, this structure having suitableconnections with the train-pipe, auxiliary reservoir, and brakecylinderat the points, respectively, marked T P for train-pipe, A R forauxiliary reservoir, and B C for brake-cylinder.

Referring iirst to the emergencyvalve mechanism, which is containedwithin the' supplemental casing 4, such casing has an end cap 5, whichcloses the outer 4end of a chamber in which the emergency-valve piston 6travels. Upon the outer end of the rod GfL of this piston is arrangedthe emergency-valve 7, which is in the form of a puppet-valveadapted toseatupon the seat 8 and to thereby normally close the port 9 throughsuch seat. The piston-rodpasses through a partition 10, but does not [ittightly therein, thereby providing a leakage or restricted feed from thetrain-pipe in to that part marked 11 of the piston-chamber formed on theright-hand side, Fig. l, of the emergency-piston, that partof thepiston-chamber on the other side of the piston being for convenienceindicated by the reference character 12. The trainpipe air passes fromthe train-pipe through the connection marked T P and through the passagemarked 13 in the supplemental casing, past the emergency-valve and feedsfreely and without obstruction to the chamber 12 through the largepassage 14n near the upper end of such supplemental casing. If desired,a light spring 15 may be employed on the outer side of theemergency-piston to assist in seating the emergency-valve after anemergency action. Upon the train-pipe reduction suitable for emergencyaction the pressure in the Achamber l2 is suddenly reduced; but thepressure in chamber l1, not being able to leak back into the'train-pipesuiciently fast, expands in such latter chamber, thereby forcing theemergency-piston outwardly and lifting the emergency-valve oif its seat,so thatthe train-pipe pressure is vented from the trainpipe directly tothe brake-cylinder through the rather large and direct passage 16, eX-tending transversely of the valve-body. The reservoir-pressure is alsoadmitted in emergency action on top of the train-pipe air thus vented tothe brake-cylinder in a `manner hereinafter explained. This direct andtransverse passage 16 is provided with a check- Valve 17, normally heldto its seat 'by the coiled spring 18.

The brake-release mechanism and the service mechanism are each operatedand under the control of separate and independent diaphragme 19 and 20,respectively, which are clamped to the valve-body by the caps 2 and 3,respectively, the diaphragm 19 being clamped directly by its cap and thediaphragmY IOO 2O indirectly'in the manner hereinafter eX- plained.

Referring first to the brake-release mechan- Ism, the brake-releasevalve (marked 21) is ar ranged to operate. i n a chamber 22 in thevalvebody and to govern a brale-releaselport123, leading to theatmosphere, such passage being formed adjacent to the release-valve in aseat or block 24, as clearly indicated in Fig. 1. The release-valve isarranged to'govern the release of pressure from the brake-cylinderthrough the transverse passage 16 and lpassage 25, connecting betweenthe transverse passage, chamber 22, and release port or passage 23.Thetrain-pipe air is fed to the auxiliary reservoir and to thebrake-release' mechanism first through a common passagel and thence byseparate lpassages 33 and 34, leading, respectively, to the auxiliaryreservoirand to the under side-of the diaphragm 19. The passage 33continues as a passage 35 through the top cap 2, past a check-Valve44,

`and through a restricted port 46, thence through passages 37 and 38 tothe auxiliary reservoir. A short passage 39 leads from passage 37 to theupper side of the diaphragm 19, so that the-latter is always exposed onits upper face to reservoir-air and on its lower face to train-pipe air.

Referring next to the service-valve meehanism as herein shown, thediaphragm 20 carries a service-valve 48, arranged to Work in a chamber49, vinterposed between the port and a passage 5T, leading from thereser- Voir through the valve-body to the chamber on the upper side ofthe diaphragm 20. The port 50 communicates with the brake-cylind erthrough the connecting-passage 52 and the 'direct transverse passage 16.If desired, a

the-brakes the reservoir-pressure will forcethe diaphragm 20 downward,and therebyopen the service-valve, and thereby permitting theauxiliary-reservoir pressure to flow from the.

passage 57 through the chamber 49 and Vports and passages 50 and 51 and16 to the brakecylinder. e

The triple valve as so far described is the same as heretofore madebyme, and it is in connection with such triple valve, and particularlywith the service mechanism thereof, that my invention in its presentembodiment is arranged to cooperate. My invention comprises means forpreventing under certain conditions the admlsslon of excess pressurefinto the brake-cylinder, or apressure in excessof'apredeterminedamount, so that the `wheels of the car cannot be slid by any excesspressure admittedto the brake-cylinder when the car is empty, and suchmeans as herein shown arefalso arranged to permit .the full pressure tobe admitted into the brake-cylinder when-the car is loaded. Furthermore,

such means which are arranged to be manuallyset to a loaded-car-positionare adapted tobe automatically returned to empty-car positionwhenever'ethe car kis 'set out from the train and is no'longer incommunication with `the airdrumon alocomotiv'e.

-brake-cylinderthe service-,valve is held closed,

and 'thereby preventedY from-fadmittingany more'pressure to thebrake-cylinder, notwithstanding furtherrreductions offtrain-pipepressure, and I also 'provide an a-rrangement for rendering suchl meansinoperative 'at the will ofthe operato1,|sothatthe full pressure may beutilized for loaded-car braking.

As herein shown, I interpose -between the bottom face of the mainvalve-body 1 and the bottom cap 3 a substantially cylindrical casing 60,which by preference serves to directly clamp the diaphragm 2O ofthefserviee mechanism in place. rlhis casing 60 is provided with achamber 60,in which is arranged a movable abutment,- in-'the presentvinstance a diaphragm 61, which is clamped-'to such-casing directly bythe bottom capi3. This dia- -phragm 61 carries a central stem or plunger62,` which projects upwardly through a stuing-box 63 to a position in`proximity to the diaphragm 2O of the servicemechanism. -Normally,-ho\vever, this plunger is positioned at such a distance fromthe `latter diaphragm as to permit the same to operate freelygand tothereb5T ad mit reservoir-pressure to the brakecylinder withoutanyinterference; but thearrangement is such that upon an excess of-pressure in the brake-cylinder the plunger is moved upwardlyA andagainstthe diaphragm 20, or rather against the nut 64, which holds theservice-valve to its diaphragm. The result of this interposition of theplunger 62.

into the path of movement ofthe diaphragm 2O is to prevent the operationof theservice mechanismand to keepl the service-valve upon its seatregardless of furthertrain-pipereductlons. To cause excess pressure mthe brakecylinder to operate the extra diaphragm 61 and -move itupwardly in the manner just explained, the lower face thereof is exposedto brake-cylinder pressure-through the passage IOO IIO

65, leading `from the transverse passage'l downwardly through thevalve-'body Il, and through the bottom cap 43 to the under side of thediaphragm' 61, as clearly indicated in Fig. l, it being understood, ashereinafter explained,ithat the interior of the casing 60- that is, thechamber 60 on the upper side of 'the diaphragm 61--is normally atatmospheric pressure. The diaphragm161 is loaded or normally presseddownwardly to theposition shown in Fig. l by means of a spring 66abutting at its lower end preferably upon' a circularsaddle 67, restingdirectly upon the diaphragm 6l tov prevent wear thereof, and at itsupper end against an adjusting-ring or -spring-seat 68, which isscrew-threaded upon that portion of the casing 60 which form's'thestung-box. This spring represents or corresponds to the predeterminedpressure which is to be admitted to the brake-cylinder for braking anempty car, and'it serves to resist that pressure from the brake-cylinderwhich,

when the brakes are applied, is pressing uppredetermined pressureadmitted to the brakecylinder, can be varied according to the directionof adjustment of the ring.

In order to adapt the car for loaded-car braking, which fis hereinaccomplished by throwing this'special mechanism out-of action, I providea transverse bore or passage through the casing 60 at one side thereofand counterbore such passage in order to providealarger chamber 69 and asmaller chamber 70, the remainder 7 lof such passage being of sucientdiameter to freely receive a rod or plunger 72, as clearly indicated inFig. 2. The outer end of the chamber 69 iis arranged to communicate withthe auxiliary reservoir through the usual passage 57, leading to theupper side of the diaphragm 2O of the service mechanism, and through abranch passage 73, leading from the passage 57, which passage 73 extendsfrom the valve-body through the casing 60 and throughaportion of thesmall cap 60b and then upwardly through aseat 74, arranged in the bottomofthe chamber 69, where it emerges or terminates as a port 75.Auxiliary-reservoir pressure is therefore always present in the passage73 and at the port 75; butthe ow of such pressure to the chamber 69 isprevented by the valve 76, which is carried-on the inner end of the rodor plunger 72. This plunger is spring-pressed toward the valve-seat bymeans of a spring 77, situated in the chamber 70, which forms the springcase or barrel therefor. The chamber 69 is normally exposed `toatmosphericpres sure,\.inasmuch as the tit of the plunger 72 in thepassage 71 is not a tight one, and likewise the chamber above thediaphragm 6l is normally exposed to atmospheric pressure, inasmuch asthe chamber (designated 6021 for convenience) is exposed to atmosphericpressure, because the same is connected with the chamber 69 by means ofa cross-passage 78, as indicated in Fig. 2. The outer end of the rod orplunger 72 which extends extraneous of the casing 60 is arranged to bedrawn outwardly manually when it is desired to adjust the apparatus forloaded-car braking, as hereinafter described, and to this end suchplun-v ger has a pin-and-slot connection with a lever 79,V pivotedintermediate its length on a fulcrum 8O on the lug or extension 81,proceeding from the casing 60, as indicated in Fig. 2. In vthe presentinstance the'pin-andslot connection is obtained through the medium of apin 82 on the rod 72 and aslot 83 in' the lever 79. This lever isprovided at its opposite ends with eyes 84 and 85, which are similar,with the exception thatthey point in opposite directions, thel eye 84being connected with a rod 86,extending transversely of the car to nearone side thereofys'o that it may be Within easy reach of the trainman,and the other eye is connected with asimilar rod 87, extending to theother side of the car. By these means an outward pull of either of thesespecial rods moves the plunger 7 2 in the same direction-that is,outwardly.

Normally the device is positioned for emptycar braking, the improvementsconstituting my invention being in operative condition and ready to moveand hold the service-valve upon its seat when the brake-cylinderpressure exceeds a predetermined amount. I/Vhen, however, it is desiredto set Vthe apparatus for loaded-car braking, the trainman pulls oneofthe rods 86 87, with the result that the plunger 72 is drawn outwardlyagainst the tension'of the spring 7 7 and the circular bead or ring 88on the upper surface of the body of the valve 76 caused to seat upon thegasket 89, arranged at one end of the chamber 69. The result of thismovement of the plunger 72 is to open the auxiliary-reservoir port andpassage and to close the passage or communication to the atmospherethrough the passage 7l. The reservoir-pressure now flows through thechamber 69, around the valve 7 6, through passage 78, and into thechamber 60, with the result that the pressure of the spring 66 upon itsdiaphragm 6l is augmented by the auxiliary-reservoir pressure, and suchdiaphragm is therefore prevented from being moved upwardly by thebrake-cylinder pressure, although such latter pressurev may be in excessof the load or amount represented by the spring 66-that is, thepredetermined degree of pressure. The diaphragm 61 and its IOC' plunger62 are vtherefore rendered inoperative and thrownfoutofvactiong so thatthey are incapable of any interference Withtheoperation of the servicemechanism,-with the resulty thatI the full amount of reservoir-air thatcan be obtained on an equalization can be admitted to thelbrake-cylinder irrespcctivefof the predetermined degree of pressure towhich the apparatus' has been set for emptyfcar braking.' As iswellknown, the pressure of the brakey system does not remainvery long o'n`alcar Which nas been set out from a live train-that is, ay trainconnected up with a locomotive or source of compessed airor in a ca-r inatrain which has been detached from the locomotive-inasmuch as the airsoon leaks away. Byzreason of rthis fact the return of my apparatus fromits manually-set position for loaded-car brakingto the-empty-carposition is automa-tic in' character, for, aswill be understood from aninspection of Fig. 2, the valve 76 after being set for loaded-car'braking is held to such set orshit'ted position by thereservoir-airagainst tension of the spring 77. When, however, such air has leaked oilfrom the car or been reduced below the degree of pressure .exerted bythe spring 77, the valve 7 6 will be seated by the spring and thevchamberv EL thereupon exhausted to atmosphere through the passage 71.

It will be understood thatvvhen the-devicev is normal-that is, incondition for empty-car braking-emergency action maybe obtained Withoutinteference from the special arrangement above described, inasmuchasvupon a sudden and considerable reduction of trainpipe pressurenecessary for emergency action the train-pipe air Will be vented to thebrakecylinder, and such pressure so admitted will be augmented bythereservoir-pressure, which is admitted by the opening of theservicevalve. Inasmuch as the pressure in the trainpipe has beenpractically or considerably depleted or reduced, the pressure on thelower side of the diaphragm20 has been correspondingly reduced, so thatthe considerable preponderance of the pressure as equalized in emergencyaction will prevent the plunger 42 from affecting the operation of theservicevalve, so that full equalization between the reservoir andbrake-cylinder can be obtained in emergency action. Y

By preference my improvements form a component part ot' the triple-valvedevice, and the same are compactly arranged in respect thereto; but itWill .be understood that the particular location and arrangement thereofare not essential and that I am not to be limited thereto exceptwhen theclaims expressly require it, inasmuch as I contemplate using myinvention Wherever applicable regardless of particular environments andposition.

I claim- 1. In a device for actuating Huid-pressure brakes, thecombination with the service-valve mechanism actuated l byy variationsinf trainpipe pressureg'of means for closing the servicevalve and actingtoso close the valveonly when the brake-'cylinder pressure exceeds'apredetermined maximum amount.

2.l Inl a device forl actuating fluid-pressure brakes,thecombinatiomWith'the'service-valve mechanism actuated byv variations intrainpipe pressure, ofy fluid pressure actuated means forclosings-theservice-valvc-and acting to so close the valve-onlyfwhen thebrake-cylinderfpressure exceeds aprcdetermin ed maximum` ramount. r y

3. Inaldevicer-forf actuating fluid-pressure bra-kes,the'combi'natiomwith the service-valve mechanismactuatedv by.variations-in tra-inpipe pressure', of means under-the con-trol ofthebrake-cylinder pressure for closingthe service-valveand actin-g v-toso closev the-valve only when'thebrake-cylinder vpressure exceeds aVpredetermined 4maximum amount.-

4; In adeviceffor actuating fluid-pressure brak-es, the combination withthe-service-'valve mechanism actuated by variations-in trainpipelpressure, ,of l-u'idpressureactuated mechanism under the control of thebrakecylinder pressure `and arrangedto hold-the service-valvc-'closedwhen the brake-cylinder pressure exceeds a predetermined -maximumamount.

5. In a device for actuating fluid-pressure brakes, the combination,with the service-valve mechanism,- of ay movable abutment under thecontroll of `the brake-cylinder pressure and inactive duringordinary-graduating action of the service-valve mechanism, said abutmenthaving-a projection arranged, When the abutment is operated by excessbrake-cylinder pressure, to cooperate with the service-valve andvholdthe same closed when the brake-cylinder pressure exceeds apredetermined maximum amount.

6. In a device for actuating fluid-'pressure brakes,the combination,with the service-valve mechanism, of a movable abutment under thecontrol of the brake-cylinder pressure, and a stem or plunger actuatedby the abutment and arranged to be projected into the path of movementof the service-valve and, when operated by excess brake-cylinderpressure, to hold such valve closed.

7. In a device for actuating fluid-pressure brakes,the combination, withthe service-valve mechanism actuated by variations in trainpipepressure, lof a movable abutmentnormally exposed on one side toatmospheric pressure and on the other .side to brake-cylinder pressurewhen the brakes are applied, and means operated by such abutment forcontrolling the action of the service-valve and arranged to close thelatter onlywhen the brake-cylinder pressure exceeds a predeterminedmaximum amount.

8. vIn a device for actuating Huid-pressure brakes, the combination,with the service-valve IOO Iov

mechanism actuatedvby variations in trainpipe pressure, of a movableabutment normally exposed on one side to atmospheric pressure and on theother side to brake-cylinder pressure when the brakes are applied, saidabutment being normally held With a yielding pressure corresponding withthc predetermined pressure to be permitted in the brake-cylinder, andmeans operated by such abutment Jfor controlling the action of theservice-valve and arranged to close the latter lwhen the brake-cylinderpressure exceeds a predetermined amount. j

9. In a device for actuating fluid-pressure brakes, the combination,with the service-valve mechanism, of a movable abutment normally exposedon one side to atmospheric pressure and on the other side tobrake-cylinder pressure when the brakes are applied, a springcooperating With the abutment and opposing the brake-cylinder pressurewith a tension corresponding with the predetermined degree of pressuredesired in the brake-cylinder, and

vmeans operated by such abutment for controlling the action of theservice-valve and arranged to close the latter when the brakecylinderpressure lexceeds a predetermined amount. i 10. In a device foractuating luid-pressure brakes, the combination, with the service-val vemechanism, of a movable abutment normally exposed on one side toatmospheric pressure and on the other side to brake-cylinder pressurewhen the brakes are applied, a spring cooperating With the abutment andopposing the brake-cylinder pressure with a tension correspondingWith'the predetermined degree of pressure desired in the brake-cylinder,means for adjusting the tension of said spring,- and means operatedbysuch abutment for controlling the action of the service-valve andarranged to close the latter when the brakecylinderpressure exceeds a-predetermined amount.

11. ln a device for actuating fluid-pressure brakes, the combination,with the service-valve mechanism, of a movable abutment normally exposedon one side to atmospheric pressure and on the other side tobrake-cylinder pressure when the brakes are applied, a springcooperating with the abutment and opposing the brake-cylinder pressurewith a tension corresponding with the predetermined degree of pressuredesired in the brake-cylinder, an adjustable spring-seat by Whoseadjustment the tension of the spring is regulated, and means operated bysuch abutment for controlling the action of the service-valve andlarranged to close the latter when the brakecylinder pressure exceeds a`predetermined amount.

12. In a device for actuating fluid-pressure brakes, the combination,with the service-valve mechanism, of a diaphragm controlled bybrake-cylinder pressure and normally subject to a pressure eq ualing apredetermined brakecylinder pressure, and a stem carried thereby andarranged to be projected to interfere With and'close the service-valvewhen the brakecylinder pressure exceeds such predetermined amount.

13. In a device Jfor actuating fluid-pressure brakes, the combination,with the service-valve I mechanism, of a diaphragm controlled bybrake-cylinder pressure, a spring opposing the brake-cylinder pressure,and a stem carried by the diaphragm and arranged to be projected tointerfere with and close the service-valve when the` brake-cylinderpressure exceeds the predetermined vamount represented by said spring.

111. In a device for actuating Huid-pressure brakes, the combination,with the service-valve mechanism, of a diaphragmv controlled bybrake-cylinder pressure, a spring opposing the brake-cylinder pressure,an adjustable seat for said spring to vary the tension thereof, and astem carried by the diaphragm and arranged to be projected to interferewithV and close the service-valve when the brake-cylinder pressureexceeds the predetermined amount. A

15. In a device for actuating fluid-pressure bra'kes,the combination,With the service-valve mechanism, of a diaphragm controlled bybrake-cylinder pressure, a spring opposing the brake-cylinder pressure,an adjustable seat for said spring to vary the tension thereof, aspring-seat on the diaphragm to receive the spring, and a stem carriedby the diaphragm and arranged to be projected to interfere with andclose the service-valve when' the brakecylinder pressure exceeds thepredetermined amount.l

16. In a device for actuating Huid-pressure brakes, the combination,with the service-valve mechanism, of a diaphragm controlled bybrake-cylinder pressure, a spring opposing the brake-cylinder pressure,a stem carried by the diaphragm and arranged to be projected tointerfere With and close the service-valve when the brake-cylinderpressure exceeds the IOO predetermined amount, and a stuHing-box for lIIS pressure brakes in which the service-valve mechanism is independentot' the brake-release and emergency mechanisms, Huid-pressure-operatedmechanism under the control of the brake-cylinder pressure for holdingthe service-valve closed when the brake-cylinder pressure exceeds apredetermined amount.

1Q. In a valve device Jfor actuating iuidpressure brakes, in which theservice-valve mechanism is independent of the brake-release andemergency mechanisms, mechanism under the control of the brake-cylinderpressure for holding the service-valve closed when the brake-cylinderpressure exceeds a predetermined amount, said last-named mechanism beingarranged to resist the brake-cylinder pressure, and means for varyingthe degree of such resistance.

20. In adevice for actuating Huid-pressure brakes, the combination, withtheservice-valve mechanism, of mechanism under the control ofbrake-cylinder pressure for holding the service-valve closed when thebrake-cylinder pressure exceeds a predetermined amount, and means forrendering said last-named mechanism inoperative at the will of theoperator.

2l. In a device for actuating fluid-pressure brakes, thecombination,with the service-valve mechanism, of mechanism under thecontrol of brake-cylinder pressure for holding the service-valve closedwhen the brake-cylinder exceeds a predetermined amount, andmanually-operated means for rendering said lastnamed mechanisminoperative.

22. In a device for actuating fluid-pressure brakes, the combination,with the service-valve mechanism, of mechanism under the control ofbrake-cylinder pressure for holding the service-valve closed when thebrake'- cylinder exceeds a predetermined amount, comprising a movableabutment having a stem arranged to be projected into the path ofmovement of the service-valve, said abutment being exposed on one sideto brake-cylinder pressure and on the other side to atmospheric pressurefor empty-car braking, and means for admitting pressure to that side ofthe abutment thus exposed to atmospheric pressure for loaded-carbraking.l

23. In a device for actuating fluid-pressure brakes, the combination,with the service-valve mechanism, of mechanism under the control ofbrake-cylinder pressure for holding the service v alve closed when thebrake cylinder pressure exceeds a predetermined amount, comprising amovable abutment having a stem arranged to be projected into the path ofmovement of the service-valve, said abutment being exposed on one sideto brake-cylinder pressure and on the other side to atmospheric pressurefor empty -car braking, and means for admitting auxiliary-reservoirpressure to that side of the abutment thus exposed to atmosphericpressure for loaded-car braking.

24. In a device for actuating'iuid-pressure brakes, the combination,with the service-valveU mechanism, of mechanism under the control ofbrake-cylinder pressure for holding the service-valve closed when thebrake-cylinder exceeds a predetermined amount, comprising' a' movableabutment having a stem arranged to be projected into the path ofmovement of the service-valve, said abutment` being exposed on one sideto brake-cylinder pressure and on the other side to atmospheric pressurefor empty-car braking, and meansV under the control ofv the operator forclosing the communication between said abutment and the atmosphere andsimultaneously admitting auxiliary-reservoir pressure to the abutment tooppose the brake-cylinder pressure.

25. In a device for actuating Huid-pressure brakes, the combination,with the service-valve mechanism, of mechanism under the control ofbrake-cylinder pressure for holding the service valve closed when thebra-kecylinder exceeds a predetermined amount, comprising a movableabutment having -a 4stem arranged to be projectedinto'the path ofmovement or the service-valve, said abutmenty being exposed on one sideto brakecylinder pressure and on the other side to atmospheric pressurefor empty-car braking, and means Jfor closingthe communicationbetweensaid abutment and the atmosphere and simultaneously admittingauxiliary-reservoir pressure to the abutment to oppose thebrake-cylinder pressure, said means comprising a valve controlling theflow of said;auxiliary-reservoir pressure, and a stem connected withsaid 'valve Jforoperating it.

26. In a device for actuating Huid-pressure brakes, the combinatoruwiththe service-valve mechanism, of mechanism under the control oi"brake-cylinder pressure for' holding the service-valve closed when thebrake-cylinder exceeds a predetermined amount, cornprisinga movableabutment having a stem arranged to be projected into the path ofmovement of the service-valve, said abutment being exposed on onesidetobrake-cylinder pressure and -on the other side to atmosphericpressure for empty-car v braking, andmeans for closing the communicationbetween said abutment and the atmosphere'andsimultaneously admittingvauxiliary-reservoir vpressure to the abutment to oppose thebrake-cylinder pressure, said means comprising a springpressed valvecontrolling the iow of said auxiliary-reser-voir pressure, and astemhaving manually-operated means for actuating the same.

27. In a device for actuating fluid-pressure brakes,the combination,with the service-valve mechanism, of mechanism under the'control ofbrake-cylinder pressure for holding the service Valve closed, when the'Vbrakecylinder exceeds a predetermined amount, comprising a movableabutment having a stem arranged to beV projected 'intothe patlr ofmovement of the service-valve, saidl abutment being exposed'on one sideto lbrake-cylinder pressure and on` the other side ltoatmospher'icpressure for empty-car braking, .said

IOO

IIO

abutment operating in a ,chamber and constantly'exp'osedtobrake-cylinder pressure on one side and on the other side normallyexposed to atmospheric air, a valve-chamber arranged at one side of andcommunicating with the abutment-chamber and normally at prising amovable abutment having a stem arranged to be projected into'the path ofmovement of the service-valve, said abutment being exposed on one sideto brake-cylinder pressure and on the other side -to atmosphericpressure for empty-car braking, said abutment operating in a chamber andconstantly exposed to brake-cylinder pressure on one side and on theother side normally exposed to atmospheric air, a valve-chamber arrangedat one side of and communicating With the abutmentchamber and normallyat exhaust, a spring-pressed valve in the valve-chamber for closing saidexhaust and atthe same time opening the chamber to auxiliary-reservoirair which is. thereby admitted to the abutmentchamber to oppose thebrake-cylinder pressure.

29. In adevice for actuating iiuid-pressure brakes, the combination,with the service-valve mechanism, of mechanism under the control ot'brake-cylinder pressure for holding the service-valve closed when thebrake-cylinder exceeds a predetermined amount, comprising a movableabutment having a stem arranged to be projected into the path ofmovement of the service-valve, said abutment being exposed on one sideto brake-cylinder pressure and on the other side to atmospheric pressurefor empty-car braking,said abutment operating in a chamber andconstantly exposed to brake-cylinder pressure on one side and on theother side normally exposed to atmospheric air, a valve-chamber arrangedat one side of and communicating With the abutment-chamber and normallyat exhaust, a valve in thevalve-chamber for closing said exhaust and atthe same time opening the 'chamber to auxiliary-reservoir air Which isservice, brake-release and emergency mechanisms, and means also arrangedWithin said casingv for closing communication betweeny the auxiliaryreservoiry and brake-cylinder and normally inactive but arranged to actwhen the brake-cylinder pressure has reached apredetermined amount,regardless of the pressure in the auxiliary reservoir.

31. In a device for braking cars according to Weight empty and loaded,the combination, With the triple-valve and the service-valve mechanismsthereof, of means arranged to close the service-valve when, in empty-carbraking, the brake-cylinder pressure reaches a predetermined amount, andmechanism for rendering said means inoperative.

32. The combination of a casing containing service, brake-release andemergency ymechanisms, the service mechanism being independent of theother mechanisms, and means also arranged in the casing for controllingthe operation of the service mechanism and arranged to hold the same toa position preventing the flow of auxiliary-reservoir pressure to thebrake-cylinder when the brake-cylinder pressure exceeds a predeterminedamount.

' 33. In a device for actuating fluid-pressure brakes of the species inwhich the service, brake-release and emergency mechanisms areindependent, physically and operatively, the combination, with theservice mechanism, of means for rendering 'the same inoperative when-the brake-cylinder pressure exceeds a predetermined amount.

34. In a valve device for actuating fluidpressure brakes in which theservice-valve is independent of the brake-release and emergency valves,means for closing the servicevalve when the brake-cylinder pressureexceeds a predetermined amount.

35. In a valve device for actuating fluidpressure brakes in Which theservice-valve 1s independent of the brake-release and emergency valves,controlling means for closing the service-valve when the brake-cylinderpressure exceeds a predetermined amount, and means for rendering saidcontrolling. means inoperative.

36. In a valve device for actuating fluidpressure brakes in which theservice-valve is independent of the brake-release and emergency valves,controlling means for closing the service-valve when the brake-cylinderpressure exceeds a predetermined amount, said controlling means beingnormally in operative condition, and means for rendering suchcontrolling means inoperative at the will of the operator.

37. In a device for actuating Huid-pressure brakes, the combination,With the servicevalve, of mechanism arranged to hold the service-valveclosed when the brake-cylinder pressure exceeds a predetermined amount,

IOO

ITO

and means for rendering saidlast-named mechl when the brake-cylinderpressure reaches or anism inoperative at the will of the operator.lexceeds a predetermined maximum amount.

38. In a device for actuatingv fluid-pressure brakes, the combination,with the service- 5 valve mechanism, of means inactive during.Witnesses:

graduation operations of the service-valve S. E. HIBBEN, but arranged toact to close the service-valve LOUIS B. AERWIN.

WILLIAM P'. A. MACFARLANE.

